Recently, consumers have expressed significant interest in “place-shifting” devices that allow viewing of television or other media content at locations other than their primary media presentation device. Place-shifting devices typically packetize media content that can be transmitted over a local or wide area network to a portable computer, mobile phone, personal digital assistant, remote television or other remote device capable of playing back the packetized media stream for the viewer. Place-shifting therefore allows consumers to view their media content from remote locations such as other rooms, hotels, offices, and/or any other locations where portable media player devices can gain access to a wireless or other communications network.
While place-shifting does greatly improve the convenience afforded to the end user, there remain some challenges related to the manner in which different media streams are presented at the end device. For instance, the digital audio samples in one media stream may be associated with a baseline or average presentation loudness or volume, while the digital audio samples in another media stream may be associated with a different baseline/average presentation loudness or volume. Thus, if the user switches between different media streams the perceived loudness may be inconsistent, and the user will therefore need to adjust the volume control on the presentation device.
Volume normalization techniques can be utilized to automatically adjust the volume perceived by the user. Some volume normalization techniques operate in the analog domain, and others operate in the digital domain. Digital volume normalization techniques are best suited for place-shifting applications because the media streams are encoded and transmitted to the presentation device using data packets. Unfortunately, existing digital volume normalization techniques tend to be ineffective and/or they introduce audible artifacts that can be distracting to the user.